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Full text of "The manufacture and properties of iron and steel"

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times all springs, tools, dies, and the like were made from either cement or crucible steel, but in late years large quantities of high-carbon metal have been produced in the Bessemer converter. The manganese in Bessemer steel is much higher than in crucible metal, and this has a tendency to cause cracks in quenching. Formerly a content of .75 to 1.10 per cent, was not uncommon, but the demands of the trade ha,ve forced an improvement in this respect. It is possible to make a better selection of the stock for an open-hearth furnace and produce a steel low in manganese, phosphorus, and sulphur. The relative merits of open-hearth and crucible steel have been vigorously discussed, but oftentimes ai comparison is made between a pure crucible, steel and an impure open-hearth metal, and the conclusion formulated that crucible steel is much superior. ISTo comparison is valid unless the steels are of the same composition, and in this latter respect it will not do to accept the unproven statements of makers. Table V-A gives analyses of three grades of steel, furnished by one of the well-known steel manufacturers of the country.
TABLE 'V-A. Commercial High Steels Not According to Specifications.
Nature of sample as marked by maker.	Composition; percent.				
	0	P	Mn	81	S
"Crucible" ..............	1.00 .94 .80	.04 .065 .072	.83 .56 .64	'    .02 .28 .19	.025 .125 .155
" Pennsylvania Ballroad spring" . " Low pnosphoru s spring" .....					
The carbon content is right, but each sample shows discrepancies between actual composition and name. Crucible steel may contain as much as .04 per cent, of phosphorus, but no purchaser expects that amount, and when this is considered in connection with the high manganese, and the absence of silicon, the natural conclusion is that the metal ran from an open-hearth furnace. The second sample was supposed to fill the Pennsylvania Eailroad specifications for springs which at that time called for phosphorus below .05 per cent., manganese below .50 per cent., and sulphur below .05 per cent., hut a glance will show the liberties that were taken. The "phosphorus" spring steel contains .072 per cent, of that element, an amount slightly under the average of common rails.